A motor-racing enthusiast is planning to unravel a 57-year-old mystery by searching for the historic grand prix car which caused the death of the driving ace who was his boyhood hero.

Maurice Owen believes that the Mercedes in which Dick Seaman was killed lies buried under a chapel in the grounds of the former Worcestershire manor house which was his family home.

Seaman was burned to death in a crash at the La Source hairpin bend on the Spa motor racing circuit during the Belgian Grand Prix on 27 June 1939.

He was the son of a wealthy British Nazi sympathiser and the only non-German member of the world-beating Mercedes motor racing team which was the pride of Nazi Germany. He started driving for the team in 1937 and won four races for them. Yet he was himself an anti-Nazi and his mother, Lilian Bettes-Seaman, who was held under house arrest during the Second World War, never forgave him when he patriotically had his silver Mercedes repainted in British Racing Green.

Mr Owen, 70, the technical director of the Morgan Motor Company, believes that after her son's death, Mrs Bettes-Seaman had the wreck of his car brought to England and buried under a chapel which she turned into a shrine in his memory. Mr Owen and a group of fellow enthusiasts are seeking permission to search for the wreckage with a thermal imaging camera in the grounds of the family's former home, Pull Court at Longdon, near Upton-upon-Severn, which is now the privately run Bredon school. The group, which includes a former motoring journalist and the American agent for Morgan Motors, is planning to make a film about the venture.

"I have been aware for some time of rumours that Dick Seaman's mother, who was an odd sort of person, brought the car back to Britain, and it is a fascinating story," Mr Owen said. "This is particularly interesting for me because I used to live near Pull Court as a boy and often went up there to talk to the mechanics as they were working on the car. I even met Dick Seaman himself once and found him a very pleasant young undergraduate. He used to test his car up and down the drive outside the house."

The theory is that Mrs Bettes-Seaman obtained the remains of the crashed Mercedes with the help of Hitler's Foreign Minister, Count von Ribbentrop, who was a personal friend and who was often a guest at Pull Court before the outbreak of war. The engine was retained by Mercedes and is now exhibited in the company's museum in Stuttgart.

Mercedes has four of the cars which made up the six-strong racing team. The sixth was owned by Nicolai Ceausescu, the late Romanian Communist dictator, and is thought to be in pieces in farm buildings somewhere in Romania.